Imidazothiazoles

Abstract

Compounds of the general formula ##STR1## have a pronounced tendency to form liquid crystalline S (smectic) phases. Thus, optically inactive compounds of the formula I also have a tilted smectic phase, in particular an S C phase, in addition to a nematic phase. In contrast, many optically active compounds of the formula I additionally have, inter alia, a tilted smectic chiral phase, in particular a chiral S C phase, in addition to a cholesteric phase. The stated compounds are therefore particularly suitable as components and as dopants, respectively, for the preparation of a very wide range of liquid crystalline mixtures. The class of compounds comprising compounds of the general formula I offers a broad range of novel components and mixtures for optimization and modification of liquid crystalline mixtures.

What is claimed is: 
     
       1. An imidazothiazole derivative of the formula ##STR7## in which the symbols m, n, R 1  and R 2  have the following meanings: m and n are 0 or 1, with the proviso that m+n=1 or 2   R 1  is R 3  or Q 1  or, if n is 0 and m is 1, also R 3  -A 3  -Z 3  -,   R 2  is R 4  or Q 2  or, if n is 1 and m is 0, also R 4  -A 4  -Z 4 , and, independently of one another,     R 3  and R 4  are each on alkenyl or alkenyl radical incorporating at least three carbon atoms in which one methylene group or a plurality of non-neighboring methylene groups are optionally replaced by --O--, --COO-- or --OOC--, and/or one hydrogen atom or a plurality of hydrogen atoms are replaced by fluorine or chlorine,   Q 1  and Q 2  are each one of the following chiral groups ##STR8## in which R 5  and R 6  are each an alkyl or alkenyl radical in which one methylene group or a plurality of non-neighbouring methylene groups may be replaced by --O--, --COO-- or --OOC--, and/or one hydrogen atom or a plurality of hydrogen atoms may be replaced by fluorine or chlorine, with the proviso that the oxygen atoms are not linked directly to the ring in Q 1  or Q 2 ,   A 1 , A 2 , A 3  and A 4  are trans-1,4-cyclohexylene or are 1,4-phenylene which is unsubstituted or monosubstituted or disubstituted by fluorine, chlorine, cyano or methyl, and   Z 1 , Z 2 , Z 3  and Z 4  are each a single bond, --CH 2  --CH 2  --, --O--CH 2  --, --CH 2  --O--, --COO--, --OOC--, --C≡C--, --(CH 2 ) 4  --, --O(CH 2 ) 3  --, --CH═CH--CH 2  O--, --OCH 2  --CH═CH--, --CH═CH--(CH 2 ) 2  -- or --(CH 2 ) 2  --CH═CH--.   
     
     
       2. An imidazothiazole derivative as claimed in claim 1, which is optically inactive and forms a tilted smectic phase. 
     
     
       3. An imidazothiazole derivative as claimed in claim 1, which is optically active. 
     
     
       4. An imidazothiazole derivative as claimed in claim 1, wherein the radicals R 3 , R 4 , R 5  and R 6  are straight-chain or branched and each have 3 to 12 carbon atoms. 
     
     
       5. An imidazothiazole derivative as claimed in claim 1, wherein A 1  and/or A 2  are 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene. 
     
     
       6. An imidazothiazole derivative as claimed in claim 1, wherein at least one of Q 1  s and Q 2  is of one of the formula i and the formula ii. 
     
     
       7. ##STR9## 
     
     
       8. A liquid crystalline mixture having at least two components, comprising a content of at least one imidazothiazole derivative of the formula ##STR10## in which the symbols m, n, R 1  and R 2  have the following meanings: m and n are 0 or 1,   R 1  is R 3  or Q 1  or, if n is 0 and m is 1, also R 3  -A 3  -Z 3  -,   R 2  is R 4  or Q 2  or, if n is 1 and m is 0, also R 4  -A 4  -Z 4  -, and, independently of one another,     R 3  and R 4  are each an alkyl or alkenyl radical in which one methylene group or a plurality of non-neighbouring methylene groups are optionally replaced by --O--, --COO-- or --OOC--, and/or one hydrogen atom or a plurality of hydrogen atoms are replaced by fluorine or chlorine,   Q 1  and Q 2  are each one of the following chiral groups ##STR11## in which R 5  and R 6  are each an alkyl or alkenyl radical in which one methylene group or a plurality of non-neighbouring methylene groups may be replaced by --O--, --COO-- or --OOC--, and/or one hydrogen atom or a plurality of hydrogen atoms may be replaced by fluorine or chlorine, with the proviso that the oxygen atoms are not linked directly to the ring in Q 1  or Q 2 ,   A 1 , A 2 , A 3  and A 4  are trans-1,4-cyclohexylene or are 1,4-phenylene which is unsubstituted or monosubstituted or disubstituted by fluorine, chlorine, cyano or methyl, and   Z 1 , Z 2 , Z 3  and Z 4  are each a single bond, --CH 2  --CH 2  --, --O--CH 2  --, --CH 2  --O--, --COO--, --OOC--, --C≡C--, --(CH 2 ) 4  --, --O(CH 2 ) 3  --,--CH═CH--CH 2  O--, --OCH 2  --CH═CH--, --CH═CH--(CH 2 ) 2  -- or --(CH 2 ) 2  --CH═CH--.   
     
     
       9. A liquid crystalline mixture as claimed in claim 8, having at least one optically active dopant and a liquid crystalline material with at least one achiral component, wherein at least one of the one or more dopants are formed from a chiral imidazothiazole derivative of the formula I and the one or more components are formed from an achiral imidazothiazole derivative of the formula I. 
     
     
       10. A liquid crystalline mixture as claimed in claim 8, which contains at least one compound from the group consisting of compounds of the formulae ##STR12## in which p is 0 or 1; q and r are 1 or 2, q+r=2 or 3;   s is 0, 1 or 2;   R 7  and R 8 , independently of one another, are alkyl, alkenyl, alkoxy, alkenyloxy, alkoxyalkyl, alkoxyalkoxy, alkanoyloxy, alkenoyloxy, alkoxycarbonyl, alkenyloxycarbonyl;   R 9  and R 12 , independently of one another, are alkyl or alkenyl;   R 10  and R 11 , independently of one another, are alkyl, alkenyl, alkoxy and/or alkenyloxy;   Z 5 , Z 6  and Z 7 , independently of one another, are a single bond, CH 2  --CH 2  or CH 2  O, and Z 6  is furthermore OCH 2 , COO or OOC;   E and F, independently of one another, are phenylene-1,4-diyl or transcyclohexylene-1,4-diyl;   X 1  and X 2 , independently of one another, are hydrogen or fluorine;   (R*) and (S*) denote the relative configurations.   
     
     
       11. An optical or electro optical apparatus containing at least one imidazothiazole derivative of the formula ##STR13## in which the symbols m, n, R 1  and R 2  have the following meanings: m and n are 0 or 1,   R 1  is R 3  or Q 1  or, if n is 0 and m is 1, also R 3  -A 3  -Z 3  -,   R 2  is R 4  or Q 2  or, if n is 1 and m is 0, also R 4  -A 4  -Z 4  -, and, independently of one another,   R 3  and R 4  are each an alkyl or alkenyl radical in which one methylene group or a plurality of non-neighbouring methylene groups are optionally replaced by --O--, --COO-- or --OOC--, and/or one hydrogen atom or a plurality of hydrogen atoms are replaced by fluorine or chlorine,   Q 1  and Q 2  are each one of the following chiral groups ##STR14## in which R 5  and R 6  are each an alkyl or alkenyl radical in which one methylene group or a plurality of non-neighbouring methylene groups may be replaced by --O--, --COO-- or --OOC--, and/or one hydrogen atom or a plurality of hydrogen atoms may be replaced by fluorine or chlorine, with the proviso that the oxygen atoms are not linked directly to the ring in Q 1  or Q 2 ,   A 1 , A 2 , A 3  and A 4  are trans-1,4-cyclohexylene or are 1,4-phenylene which is unsubstituted or monosubstituted or disubstituted by fluorine, chlorine, cyano or methyl, and   Z 1 , Z 2 , Z 3  and Z 4  are each a single bond, --CH 2  --CH 2  --, --O--CH 2  --, --CH 2  --O--, --COO--, --OOC--, --C≡C--, --(CH 2 ) 4  --, --O(CH 2 ) 3  --,--CH═CH--CH 2  O--, --OCH 2  --CH═CH--, --CH═CH--(CH 2 ) 2  -- or --(CH 2 ) 2  --CH═CH--.   
     
     
       12. An imidazothiazole derivative of the formula ##STR15## which is optically active and in which the symbols m, n, R 1  and R 2  have the following meanings: in which the symbols m, n, R 1  and R 2  have the following meanings:   m and n are 0 or 1,   R 1  is R 3  or Q 1  or, if n is 0 and m is 1, also R 3  -A 3  -Z 3  -,   R 2  is R 4  or Q 2  or, if n is 1 and m is 0, also R 4  --A 4  --Z 4  --, and, independently of one another,     R 3  and R 4  are each an alkyl or alkenyl radical in which one methylene group or a plurality of non-neighbouring methylene groups are optionally replaced by --O--, --COO-- or --OOC--, and/or one hydrogen atom or a plurality of hydrogen atoms are replaced by fluorine or chlorine,   Q 1  and Q 2  are each one of the following chiral groups ##STR16## in which R 5  and R 6  are each an alkyl or alkenyl radical in which one methylene group or a plurality of non-neighbouring methylene groups may be replaced by --O--, --COO-- or --OOC--, and/or one hydrogen atom or a plurality of hydrogen atoms may be replaced by fluorine or chlorine, with the proviso that the oxygen atoms are not linked directly to the ring in Q 1  or Q 2 ,   A 1 , A 2 , A 3  and A 4  are trans-1,4-cyclohexylene or are 1,4-phenylene which is unsubstituted or monosubstituted or disubstituted by fluorine, chlorine, cyano or methyl, and   Z 1 , Z 2 , Z 3  and Z 4  are each a single bond, --CH 2  --CH 2  --, --O--CH 2  --, --CH 2  --O--, --COO--, --OOC--, --C≡--C--, --(CH 2 ) 4  --, --O(CH 2 ) 3  --,--CH═CH--CH 2  --O--, --OCH 2  --CH═CH--, --CH═CH--(CH 2 ) 2  -- or --(CH 2 ) 2  --CH═CH--.   
     
     
       13. An imidazothiazole derivative as claimed in claim 12, wherein the radicals R 3 , R 4 , R 5  and R 6  are straight-chain or branched and each have 3 to 12 carbon atoms. 
     
     
       14. An imidazothiazoles derivative as claimed in claim 12, wherein at least one of A 1  and A 2  is 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene. 
     
     
       15. An imidazothiazole derivative as claimed in claim 12, wherein at least one of Q 1  and Q 2  is of the formulae i or ii.